I'm personally torn on RSS readers. Admittedly, I'm an almost entirely unproductive person lately, so I can't claim that it's because RSS is getting in the way of other things. My chief suspicion is that as the number of subscriptions goes up, the propensity to fly through headlines rises as well, and so too does the efficiency of applying whatever criteria normally applies in choosing whether or not to read past a headline. What normally would be signal gets converted to noise because of the quantity needed to be consumed. Of course, one can always lower the number of subscriptions, but on the other hand, as one approaches lower bounds, the less sense RSS makes: one can simply and probably with more aesthetic pleasure, just make rounds to the website. Another point: there's more information and more of interest in a website than what gets printed as words in an article or in the images or whatever media that accompanies that article. And this is another suspicious element of RSS readers: they divorce content from the context in which it "originally" appears (scare quotes because of complexity). One can learn a good lot of important stuff about a content provider by looking at that provider's website, layout, design, ad priorities, etc. And not only about that provider, but about just what the hell the web looks like these days. If all I did was read via RSS, I'd probably have no clue. And more over, if all anybody ever did was read via RSS, websites themselves would be something else entirely and that something else probably wouldn't be much to look at.
So really that's two chief suspicions: one, it's hard to find an optimal number of subscriptions (or even if there is such a thing); and two, RSS annihilates the experience of everything it can't contain.
(I said I was torn, but I think I've started to convince myself that maybe I need to ditch Google Reader...)